Question

If you’re opening connections usually what you do is a try-catch-finally

try {
    doSomething();
} catch(Exception e) {
    // handle the exception
} finally {
    close();
}

In my scenario I’ve two catch and two different closing: close() in the normal case and closeStrange() if a StrangeException is thrown.

I came up with something like this:

try {
    doSomething();
} catch(StrangeException e) {
    closeStrange();
    throw new MyExc(e);
} catch(Exception e) {
    close();
    throw new MyExc(e);
}
close();

I would like to know if handle this situation in this way it’s safe.

EDIT:

Probably it wasn’t clear: I want just one of the closing to be called.
closeStrange() if the StrangeException is thrown,
close() if another Exception or none is thrown.

Answer 1

No, the way you’re handling this at the moment isn’t safe:

• You’re not using a finally block, so any non-Exception that’s thrown will leave you without closing the connection
• You’re “handling” any exception, which is almost certainly not appropriate

You probably want:

boolean closedStrangely = false;
try {
   ...
} catch (StrangeException e) {
    closeStrangely();
    closedStrangely = true;
    throw e; // Or maybe not, or maybe throwing some custom exception
} finally {
    if (!closedStrangely) {
        close();
    }
}

Note that if closeStrangely() throws an exception, this will attempt to close it “normally”. If you don’t want that behaviour, set closedStrangely to true before calling closeStrangely.

EDIT: Even if you want to throw a custom exception in some cases, you almost certainly shouldn’t be catching Exception.